The scandium effect in multicomponent alloys

Abstract

Despite its excellent elemental properties, lightweight nature and good alloying potential, scandium has received relatively little attention in the manufacturing community. The abundance of scandium in the Earth's crust is quite high. It is more abundant than silver, cobalt, lead and tin. But, because scandium is so well dispersed in the lithosphere, it is notoriously difficult to extract in commercial quantities-hence low market availability and high cost. Scandium metallurgy is still a largely unexplored field-but progress is being made. This review aims to summarise advances in scandium metallurgical research over the last decade. The use of scandium as a conventional minor addition to alloys, largely in structural applications, is described. Also, more futuristic functional applications are discussed where details of crystal structures and peculiar symmetries are often of major importance. This review also includes data obtained from more obscure sources (especially Russian publications) which are much less accessible to the wider community. It is clear that more fundamental research is required to elevate the status of scandium from a laboratorybased curiosity to a mainstream alloying element. This is largely uncharted territory. There is much to be discovered.

High-pressure high-temperature tailoring of High Entropy Alloys for extreme environments

“…Springing from its extraordinary influence on microstructure and mechanical properties of Al-based alloys, the term "scandium effect" came to define the benefits brought about by the precipitation of Sc-containing intermetallics in multicomponent alloys [52,53]. The addition of small (≤ 3 at.%)…”

Scandium Recovery from an Ammonium Fluoride Strip Liquor by Anti-Solvent Crystallization

“…Currently more than 90% of the annual global production of Sc is used for the production of SOFCs [3]. Scandium also finds use in, e.g., laser garnets, as phosphors for light emitting diodes and as an alloying element for aluminium [5][6][7]. The aluminium scandium alloys have high strength, are corrosion resistant and allow welding without loss in strength, which makes them attractive for the aerospace and automotive industries [3,7].…”

Formation and Disruption of W-Phase in High-Entropy Alloys

“…In the current study, we focus on the key role played by multicomponent intermetallic compounds in the phase formation of equimolar HEAs containing elements likely to form complex ordered binary and especially ternary phases, such as Al, Cu and Sc [11]. We present the formation and disruption of ternary Al-Cu-Sc intermetallic compounds (Al 4 Cu 4 Sc and Al 2 Cu 3 Sc) in the equimolar AlCrCuScTi alloy.…”